title: Abnormalities in the alternative pathway of complement in children with hematopoietic stem cell transplant-associated thrombotic microangiopathy.
abstract: Hematopoietic stem cell transplant (HSCT)-associated thrombotic microangiopathy (TMA) is a complication that occurs in 25% to 35% of HSCT recipients and shares histomorphologic similarities with hemolytic uremic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP). The hallmark of all thrombotic microangiopathies is vascular endothelial cell injury of various origins, resulting in microangiopathic hemolytic anemia, platelet consumption, fibrin deposition in the microcirculation, and tissue damage. Although significant advances have been made in understanding the pathogenesis of other thrombotic microangiopathies, post-HSCT TMA remains poorly understood. We report an analysis of the complement alternative pathway, which has recently been linked to the pathogenesis of both the Shiga toxin mediated and the atypical forms of HUS, with a focus on genetic variations in the complement Factor H (CFH) gene cluster and CFH autoantibodies in six children with post-HSCT TMA. We identified a high prevalence of deletions in CFH-related genes 3 and 1 (delCFHR3-CFHR1) and CFH autoantibodies in these patients with HSCT-TMA. Conversely, CFH autoantibodies were not detected in 18 children undergoing HSCT who did not develop TMA. Our observations suggest that complement alternative pathway dysregulation may be involved in the pathogenesis of post-HSCT TMA. These findings shed light on a novel mechanism of endothelial injury in transplant-TMA and may therefore guide the development of targeted treatment interventions.
authors.affiliation: Division of Bone Marrow Transplantation and Immune Deficiency, Cincinnati Children's Hospital Medical Center, Cincinnati, OH;
authors.forename: Sonata
authors.initials: S
authors.lastname: Jodele
authors.forename: Christoph
authors.initials: C
authors.lastname: Licht
authors.forename: Jens
authors.initials: J
authors.lastname: Goebel
authors.forename: Bradley P
authors.initials: BP
authors.lastname: Dixon
authors.forename: Kejian
authors.initials: K
authors.lastname: Zhang
authors.forename: Theru A
authors.initials: TA
authors.lastname: Sivakumaran
authors.forename: Stella M
authors.initials: SM
authors.lastname: Davies
authors.forename: Fred G
authors.initials: FG
authors.lastname: Pluthero
authors.forename: Lily
authors.initials: L
authors.lastname: Lu
authors.forename: Benjamin L
authors.initials: BL
authors.lastname: Laskin
mesh_terms: D000293:Adolescent; D001323:Autoantibodies / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D003170:Complement Pathway, Alternative; D003165:Complement System Proteins / Q000235:genetics* / Q000276:immunology; D017353:Gene Deletion; D005838:Genotype; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects*; D006801:Humans; D057049:Thrombotic Microangiopathies / Q000209:etiology*
chemical_list: D001323:Autoantibodies; D003165:Complement System Proteins